Răspuns :
x-x*15:100=34
x-15x:100=34
15x:100=x-34 |*100
15x=100x-3400
100x-15x=3400
85x=3400
x=3400:85
x=40
x-15x:100=34
15x:100=x-34 |*100
15x=100x-3400
100x-15x=3400
85x=3400
x=3400:85
x=40